One clinical suggestion that HIV may be activated upon exposure to steroid hormones is the observation that HIV p24 antigenemia is more frequently found in pregnant rather than non-pregnant women and that this antigenemia disappears after parturition. Transcription from the HIV-LTR was therefore studied in the presence or absence of hormonal stimuli in tissue culture cells and transgenic animals. In the presence of Dexamethasone transcription from the HIV-LTR in tissue culture cells was elevated at least 4-fold. Moreover expression from the HIV-LTR was elevated in transgenic elements during pregnancy (1) suggesting that steroid hormones may contribute to HIV expression during pregnancy.